# Maths Trick that will make you a genius

In this tutorial, we are looking at the fast way of multiplying two two-digit numbers together. First, we’ll see if you can multiply some numbers together. I’ll give you a question which is twenty-one times thirty-one. I’ll give you six seconds to work that out. Go! So time’s up. So if you got the answer of 651, you did well you got the right answer. If you were busy reaching for the calculator but couldn’t find it in time, bad luck, but you shouldn’t need a calculator. I’ll show you how to work it out quickly.

To get the first number of our answer, we multiply the first digits in our two numbers here, so 2 x 3 is 6, and we have the first part of our answer. We leave a blank space. To get the last number of our answer, we multiply the last digits of our two numbers here, So 1 x 1 is 1. There is a trick to get the middle part of this number here. We multiply 1 and 2 and 1 and 3, adding the two answers together. So 1 x 2 is 2, 1 x 3 is 3. We add 2 and 3 together and get 5. Therefore, the answer is six hundred fifty-one (651). Hey, pretty easy? We’ll have a look at another one. So, what about 43 times 21? A little bit harder this time. See how you go. Have you got the answer yet? I’ll start working through this one.

So again, 4 x 2 is 8. We leave the blank space 1 x 3 = 3. 1 x 4, and we add this to 3 x 2, so 1 x 4 is 4, and 3 x 2 is 6. Then we add these together. We get the answer of 10. This leads to a problem that is a little tricky to understand too. There is only one space here. We only have space to fit one digit, so the digit it puts in out of this ten is the zero, and for the one, We carry this across and we add it to 8. The answer we get is 1 + 8 is 9 0 3. Let’s have a look at one more question. What is the answer for 42 times 63?

First number 4 x6. Remember to leave a space. We get 24. 2 x 3 is 6. We multiply, 4 x 3 is 12 and 6 x 2 is 12, and 12 + 12 is 24. Put 4 in the middle space and carry on 2 to the next left number. So what answer did we get? Two thousand six hundred and forty-six. That’s the right answer! Pretty cool, right? So if you practice these, you will get really good at them and really fast. Your teacher will be utterly astounded by how good you are. Everyone will think you’re a genius! You may make a few mistakes. We all make them.